Improvement in piston-valves



W C. Ross. Piston-Valve.

1510.199865. Patented Jan. 29, 187s.

jig. f.

N. PETERS. FHOTOYLITHOGHAFHER, WASHINGTON. D C.

UNITED' STATES' PATENT OFFICE-L VVILLIM C. ROSS, OF CINCINNATI, OHIO.

IM PROVEM ENT IN VP|STON VA| 'VES.

Specification forming part of Letters Patent N0. 199,865, dated January29, 1878; application filed l December 18, 1877.

ton-valve,.0f an auxiliary piston-valve, which mechanically starts themain valve in shifting, and also governs the ports through which steamis introduced and exhausted, to complete the movement of the main valve.

It further consists in so constructing the v valve that the piston-headsof the auxiliary valve serve to conine the steam admitted to thevalve-chest, so that the latter may be constructed without heads, andthus admit of the withdrawal of the valves at any time for examinationand repairs without disturbing` any joints.

In the annexed drawings, Figure l is a sectional elevation of myimproved piston-valve, showing` its application to a steam-pump. Fig. 2is a plan of the valve, showing the whole of the chest and one-halfofthe valves in section. Fig. 3 is a front elevation of the same. Fig. 4is a transverse section.

The' same letters of reference indicate identical parts in all thegures.

The valve-chestA has a central bore or valvel chamber extending entirelythrough it from end to end. In this instance, the valve-chamber is ofuniform diameter throughout. The several piston-heads of the main andauxiliaryvalves are snugly itted therein, the heads B and Bl of theauxiliary valves rigidly secured to or formed on the stem B2, beingprovided with glands C and C and suitable packing, to vform tightsteam-joints. The heads of the auxiliary valve are provided withrecesses or annular grooves b and b', respectively, which communicatethrough holes c and c with the valvechamber. The main valve is fitted toslide on the stem B2, between the heads of the auxiliary valve, andconsists of three heads, D, D1, and D2, imited by hubs, or in any othersuitable manner, so as to move together.

The diiference between the length of the main valve and the distancebetween the heads -throw of the main valve.

of the auxiliary valve is determined by the On one side of thevalve-chamber the chest is provided with a steam-chamber, E, and ou theother side with an -exhaust-chamber, F. The steam-chamber E communicateswith the valve-chamber through the main steam-ports e and el, which arecon. trolled by the heads D and Dl of the main valve, and also throughthe auxiliary port-s c2 and e2, which are controlled by the heads of theauxiliaryvalve. The exhaust-steam from the cylinder passes from thevalve-chamber to the exhaust-chamber F through the main exhaustport j',governed by the head D2 of the main valve, and the steam utilized inshifting the main valve escapes to the exhaust-chamber alternatelythrough the auxiliary exhaustports f1 and f2, which are controlled bythe heads of the auxiliary valve. 'Ihe cylinderports G and Gr of thechest lare on opposite sides of the head D2, and are controlled by theheads D and Dl of the main valve.

The valve-stem B2 carries tappets B3 andB,

which are alternately struck to initiate the shifting of the valve by anarm, H, on the main piston-rod I of the engine, just before the pistoncompletes the stroke.

The operation of the valve is as follows: In the position of the valveshown in Fig. 1, the main steam-port eis uncovered, so thatlive steamenters the cylinder through portG, and drives the piston from left toright. Of the auxiliary steam-ports, e2 is closed and e3 open, while ofthe auxiliary exhaust-ports, f1 is open and f 2 closed, so that the mainvalve is held against the head B of the auxiliaryvalve by the pressureof the steam between the respectivel heads Bl and D1 of the said valves.Just before the main piston of the engine completes its stroke in thisdirection, the arm H on its rod strikes the tappet B4 on the valve-stemB2, and moves the auxiliary valve far enough by the time the stroke iscompleted to cover auxiliary Vsteam port e3 and uncover auxiliarysteam-port e2. At the same time the auxiliary exhaust f2 is uncovered,to admit of the escape of the steam confined between the respectiveheads Bl and D1 of the valves, and the auxiliary exhaust-port f1 iscovered. The main valve is also pushed to the right by the head B of theauxiliary valve by the 4same movement, and

begins to cover main steam-port c, without, however, uncovering as yetmain steam-port el, which is not effected until the main valve isfurther moved by the pressure ofthe steam behind its head D,whereby itis iinally thrown against the head B1 of the auxiliary valve, so as toclose port e and establish communication between ports el and G at thesame time that communicationis openedbetween G and ports f. Thecylinder-ports G and Gr are always open, and in shifting the valve itsopen main steamport 'remains open until the main valve is moved bysteam-pressure. The engine will therefore start from any point in thestroke.

The initiatory mechanical impulses given by the auxiliary valve to themain valve in shifting will prevent any sticking of the latter.

What I claim as my invention, and desire to secure by Letters Patent,is-

l. In a piston-valve, the combination, substantially as specified, ofthe main valve, the movement of which in shifting is initiatedmechanically and completed by steam, and an independent auxiliary valve,which is moved mechanically only, merely starting the main valve `andreversing the ow of the steam acting thereon.

2. In a piston-valve, the combination, substantiallylas specified, of anindependent auxiliary valve, moved mechanically only, and a main valvetted to slide between heads of the auxilary valve, which mechanicallyinitiate the movement of the main valve in shifting, besides controllingthe ports through which steam enters to complete such shifting of themain valve.

3. The combination, substantially as specitied, of the triple-headedmain valve, the cylinder-ports, the main exhaust-port, the mainsteam-induction ports of the valve-chest, the double-headed auxiliaryvalve, whose heads are provided with steam-passages, and the aux-:iliary steam and exhaust ports of the valvechest.

4. The combination, substantially as specied, of the open-endedvalve-chamber, the double-headed auxiliary valve, and the main valveconfined between the heads of the auxiliary valve, so that both valvescan be drawn together endwise from out of the open-ended valve-chamber.

In testimony whereof Ihave signed myname to the foregoing specication inthe presence of two subscribing witnesses.

- WILLIAM G. ROSS. Vitnesses:

FRANK CALDWELL,

PATTERSON A. REECE.

